Cancel something
we cancel x's
multiply 1st equation by 5 and 2nd by 7 and add them
-35x-30y=-5
<u>35x-28y=7 +</u>
0x-58y=2
-58y=2
divide both sides by -58
y=-1/29
sub back
5x-4(-1/29)=1
5x+4/29=1
minus 4/29 from both sides
note, 1=29/29
5x=25/29
divide bot sides by 5 (or times 1/5)
x=5/29
(5/29,-1/29)
We have been given that the standard deviation of a group of 20 scores is 15 and we are asked to find variance.
Since we know variance is square of standard deviation. In order to find out the variance of the given data we have to take the square of 15.
Therefore, our variance is 225.
Given:
And
Required:
To find the two possible values of c.
Explanation:
Consider
So
And also given
Now from (1) and (2), we get
Now put a in (1) we get
We can interpret that either of a or b are equal to 3 or 5.
When a=3 and b=5, we have
When a=5 and b=3, we have
Final Answer:
The option D is correct.
31 and 41
It will take him 28 weeks. If he already has $60 of $200 saved, you would do 200 - 60. That would give you 140. To find out how long it would take him to make $140, you would have to do 140 divided by 5 to get the number of weeks.